Recently, instead of conventional cathode-ray tubes, new display devices having a thin and flat shape using a liquid crystal or an electroluminescence is being widely used. A liquid crystal display as a representative new display device has not only a thin shape and a light weight but also a characteristic capable of being driven at a low voltage. The liquid crystal display includes a liquid crystal panel, in which a liquid crystal is sealed between two substrates as a main component. One of the two substrates is an array substrate, in which a plurality of pixels is disposed in a matrix form to configure a display area. The other substrate is an opposite substrate (color filter substrate), in which a color filter or a black matrix (light shielding layer) corresponding to each pixel is disposed to be opposite to the array substrate.
Specifically, a thin film transistor (TFT) type liquid crystal display can display a high-quality image having little crosstalk, because the TFT is provided in the each pixel on the array substrate as a switching element and the each pixel can independently maintain voltages for driving the liquid crystal. The each pixel includes a scanning line (a gate line) to control ON and OFF of the TFT, and a signal line (a source line) to input an image signal. Generally, the each pixel corresponds to an area surrounded by the scanning line and the signal line across the scanning line.
Since the scanning line and the signal line are generally formed of an opaque metallic layer having a small specific resistance, it is preferable that a ratio of the opaque metallic layer to an area of the pixel set to be small, in order to increase an aperture ratio (light transmittance). In addition, it is preferable that an area of the black matrix (light shielding layer), which is formed on the opposite substrate, to shield unnecessary light-leakage from the pixel set to be small.
In general, the TFT liquid crystal display requires one scanning signal line and one signal line for every pixel. However, when there are a number of signal lines, an expensive driving circuit is needed to drive the signal lines, thereby increasing the manufacturing cost of the liquid crystal display.
Accordingly, JP-A-2000-035589 and JP-A-2006-178461 disclose a configuration, in which two pixels adjacent to both sides of adjacent signal lines are driven by one signal line so that the number of signal lines is reduced by half.
Instead, although the number of scanning lines increases twice, a scanning line driving circuit is a simple shift resistor circuit that performs merely ON and OFF of the TFT in sequence. Meanwhile, a signal line driving circuit converts a digital signal of an image to an analog voltage signal and temporarily maintains the signal. Accordingly, the scanning line driving circuit is low cost as compared with the signal line driving circuit, and the configuration in which the number of the signal lines is reduced by half can reduce the manufacturing cost of the liquid crystal display.
On the other hand, in order to achieve the characteristic of a wide viewing angle, JP-A-2010-191410 discloses that a FFS liquid crystal display which is a kind of In-Plane Switching modes. In the FFS liquid crystal display, a pixel electrode and a common electrode, which generates electric fields to drive the liquid crystal, are formed on the array substrate and laminated with sandwiching an insulating layer. An upper electrode includes slits formed as a plurality of openings and the liquid crystal is driven by a fringe electric field generated between a lower electrode and the upper electrode through the slits. In the pixel electrode and the common electrode, one electrode may be used as the upper electrode and the other electrode may be used as the lower electrode. In general, in the FFS liquid crystal display, the pixel electrode and the common electrode are formed by a transparent conductive layer such as ITO (Indium Tin Oxide). Accordingly, a film portion of the pixel electrode and the common electrode is capable of light transmitting by the fringe electric field.
However, when the configuration that the number of signal lines is reduced by half is applied to the liquid crystal display, in order to shield the light leakage between the pixels, the black matrix needs to be disposed even on a area, in which signal line is not disposed between two adjacent pixels, of the opposite substrate as the same as a area in which the signal line is disposed. As a result, since the number of scanning lines becomes twice, there is a problem in that the aperture ratio of the pixel becomes smaller than that of a general configuration. Specifically, when the configuration that the number of signal lines is reduced by half is applied to the liquid crystal panel and liquid crystal display of the FFS type, a pixel configuration capable of increasing the aperture ratio is not fully considered.
In view of the above, the present disclosure is to provide a liquid crystal panel. Specifically, when the configuration that the number of signal lines is reduced by half is applied to the liquid crystal panel and liquid crystal display of the FFS type, the liquid crystal display capable of suppressing deterioration of the aperture ratio and increasing the aperture ratio as compared with the case where the configuration, in which the number of signal lines is reduced by half, is simply applied to a background pixel configuration.